Film bags are commonly used in supermarkets, department stores and similar applications. These bags have advantages in that they are relatively inexpensive to produce, provide substantial carrying capacity and may include easily used handles. In order to make these bags easier to handle and easier to fill, they are usually used in combination with a dispensing rack or hook. Dispensing racks typically include a pair of horizontally oriented arms from which the bags are suspended by means of holes in upper portions of the bags. If the bags can be made to open as they are pulled from the dispensing rack or hook, they become substantially easier to use. Various techniques have been developed for causing film bags to open as they are removed from dispensing racks or hooks.
U.S. Patent Application No. 2005/0087542, issued to Bazbaz is directed to a tabless, self-opening T-shirt-styled film bag is provided having a handle, stress relief notch, and mounting tab structure for providing a wide-opening bag mouth and a bag having high weight carrying capacity. Handles have a narrow upper portion, a wide middle portion and a narrow lower portion. Handle mounting apertures are provided in the wide middle portion, which projects inwardly above the mouth of the bag. The handle mounting apertures are formed by a blade having an elongate section that is bent to form an obtuse angle.
The handle mounting aperture has a sufficient width for accommodating arms of a dispensing rack and a height about three times as great as the width. The bag has a central mounting tab extending above the mouth of the bag and between the handles. A stress relief notch having a reasonably tight radius of curvature is provided between each handle and the mounting tab. The mounting tab has a mounting aperture formed by two blades meeting at a sharp corner, the corner having essentially no radius of curvature. A severable region is provided between the corner and an outer edge of the mounting tab, which can tear as the bag is removed from a mounting hook on a dispensing rack. Multiple bags are aligned and bonded together to provide a unitary pack, where pulling one bag off a dispensing rack pulls an adjacent bag open.
U.S. Pat. No. 4,676,378 issued to Baxley et al., discloses a bag pack comprising a stack of film shopping bags that are bound together and mounted on a rack in such a manner that as one is removed from the rack, the next is opened and remains on the rack to receive material therein.
The rack that is used in this invention for the bag pack comprises a flat base with a pair of laterally spaced support arms to accommodate fully expanded bags with handles engaged with the support arms. A transverse member extends between the support arms to support a tab receiving hook element for engagement through the tab apertures. When the bag pack is produced, and either prior to or simultaneously with the forming of a cut line through the stacked bag handles, the flaps are bonded together throughout the full stack. This is done by use of a heated pin or rod extended centrally through the flaps to directly heat seal the flaps together.
U.S. Pat. No. 6,105,780, issued to Nguyen describes a bag and dispensing system wherein the thermoplastic bag to be dispensed may be retained in an open position, to allow for the loading thereof with contents for carrying, such as purchased goods or the like. The system is further configured such that the loaded bag, when dispensed, draws the next bag in the stack forward into an open loading position such that it is ready to be loaded with goods without further manipulation by the attendant. The preferred embodiment of the present invention teaches the utilization multi-edged punch applied to the handle area of the bags to hold said handles together for handling of the bag pack, and for facilitating opening of the next bag in the stack on the rack, when a loaded bag is removed.
The preferred embodiment of the present invention utilizes co-extruded film, wherein there is provided a high density film having bonded thereto a lower density film of lesser density than said high density film, such that said lower density film forms the exterior side of said co-extruded film. The co-extruded film is then corona treated at a higher energy level than that recommended for facilitating a printing surface on said film. The film is then die-cut to form bag packs, and simultaneously punched with the multi-faceted punch in the area of the handles. This punch impacts the film forming the bag walls, melding the adjacent walls together in a releasable fashion, allowing self opening of said bags.
U.S. Pat. No. 5,207,328, issued to Huang et al. is directed to a pack of self-opening bags with a front, rear, and co-joined side walls, with front and rear tabs extending from top edges of the front and rear walls. The tabs have a curved aperture slits therein, and the tabs are frangibly adhered together with contact adhesive. The slit has a main cut section, a first curved end section at one end, and a second curved end section at the opposite end. The first curved section has a curve that extends upwardly and inwardly from the main cut section. The second curved section has a substantially semi-circular curve that extends from the main cut section in a direction towards the bottom edge of the tab and has an end that is substantially perpendicular to and adjacent the main cut section. In one embodiment, the first curved section is dashed.
U.S. Patent Application No. 2002/0108882 issued to DeMatteis is directed to a tab for mounting a bag bundle on a retaining hook of the type having an upwardly bent hook is shown configured in a bundle of bags. The bundle of bags has at least a leading bag and a plurality of trailing bags. There is at least one tab attached to one bag wall of each bag. This tab is in alignment with like tabs from like bag walls. The tab includes a flanged aperture including at least one peak, with this peak protruding inwardly toward and to the aperture for contact with the upwardly bent hook whereby the tabs are bent out of alignment with the upwardly shaped hook.
U.S. Pat. No. 4,636,191 issued to Piggott discloses a bag making machine for producing bags from an elongate strip of plastic web material. The disclosure relates to various improvements in the bag making machine such as the apparatus for cutting the bag handle aperture. The apparatus includes at least one circular cutting blade having a plunger movable relative thereto within its cutting periphery. The plunger includes a web piercing member on its leading face which member positively holds the web material relative to the cutting blade and plunger.
U.S. Patent Application No. 2004/0074364, issued to Prudhomme describes a multiple variable punch assembly is configurable for punching holes and slits in a plastic film material. The assembly has frame is positioned below the plane of film with one or more transverse carriages positioned to slide on the sides of the frame. Each of the carriages has side plate members, and upper and lower rails extending across the frame in the transverse direction. The upper rail is positioned above the plane of the film and the lower rail is positioned directly below the upper rail and below the film web plane. The positions of the carriages can be adjusted along the frame in the machine direction. The punch head assemblies are adjustably mounted the carriages, with an upper plate fitted onto the upper carriage rail and a lower backing plate situated beneath it on the lower carriage rail. An alignment pin can be inserted into aligned holes for positioning the upper plate and the lower backing plate. An auxiliary carriage can be mounted on one of the main carriages, and provides a pair of auxiliary rails for mounting an additional punch head.
While other variations exist, the above-described designs for self-opening bag packs are typical of those encountered in the prior art. It is an objective of the present invention to provide for a film bag pack that is suitable for use with standardized dispensing racks and includes a self-opening feature. It is a further objective to provide this capability in a bag pack that includes bags that are durable, break-resistant and easily produced. It is a still further objective of the invention to provide the above-described bag packs without the need for localized compressed areas in the bag pack. Finally, it is an objective of the invention to provide bags that open with uniform force from the first bags of the pack to the last.
While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.